This invention relates to methods for treating hot flashes. According to another aspect, the invention pertains to compositions useful in treating hot flashes.
Hot flashes are mostly caused by the hormonal changes of menopause, but can also be affected by lifestyle and medications. A diminished level of estrogen has a direct effect on the hypothalamus, the part of the brain responsible for controlling appetite, sleep cycles, sex hormones, and body temperature. The drop in estrogen confuses the hypothalamus—which is sometimes referred to as the body's “thermostat”—and makes it read “too hot.”
The brain responds to this report by broadcasting an alert to the heart, blood vessels, and nervous system to get rid of the heat. The message is instantly transmitted by the nervous system's chemical messenger, epinephrine, and related compounds: norepinephrine, prostaglandin, serotonin. The heart pumps faster, the blood vessels dilate to circulate more blood to radiate more heat, and the perspiration glands release perspiration to cool the body off even more.
This heat-releasing mechanism is how the body prevents overheating in the summer. But, when the process is triggered instead by a drop in estrogen, the brain's confused response can make the person very uncomfortable. Some women's skin temperature can rise 6° C. during a hot flash. The body cools down when it shouldn't and perspiration leaves the person soaking wet.
Eighty-five percent of the women in the United States experience hot flashes of some kind as they approach menopause and for the first year or two after their menstrual periods stop. Between 20 and 50% of women continue to have them for many more years. As time goes on, the intensity decreases.
There is considerable variation in time of onset, duration, frequency, and the nature of hot flashes. An episode can last a few seconds or a few minutes, occasionally even an hour, but it can take another half hour for the person to feel well again. The most common time of onset is between six and eight in the morning, and between six to ten at night.
Most women have mild to moderate hot flashes, but about 10-15% of women experience such severe hot flashes that they seek medical attention. The faster the person goes through the transition from regular periods to no periods—the peri-menopause or climacteric—the more significant the hot flashes will be.
Women experiencing hot flashes may encounter a variety of symptoms, including a feeling of mild warmth to intense heat spreading through the upper body and face, a flushed appearance with red, blotchy skin on the face, neck and upper chest, rapid heartbeat, perspiration (mostly on the upper body) and a chilled feeling as the hot flash subsides.
Aside from obvious techniques such as wearing light clothing, using a fan, drinking cold drinks, controlled breathing, etc., the prior art has suggested a number of non-prescription dietary supplements to curb hot flashes, such as black cohosh, soy, red clover, and vitamin E. However, none of these have proven effective in clinical trials.
Low doses of some anti-depressants have been shown to decrease hot flashes in some clinical trials, notably selective serotonin reuptake inhibitors and norepinephrine reuptake inhibitors. There are potential side effects from these medications, such as nausea, dizziness, weight gain and sexual dysfunction.
Other prescription medications have provided some relief from hot flashes, such as Gabapentin (Neurotinin) and Clonidine, but, again, side effects such as drowsiness, dizziness, nausea, imbalance, dry mouth and constipation may limit use of the drugs.
Hormone therapies have proven most effective, such as estrogen therapy and progesterone therapy and combinations of estrogen and progesterone. However, there are definite risks to hormone therapy such as increased risk of breast cancer, stroke and heart disease.
Accordingly, it would be highly desirable to provide a treatment for hot flashes which is effective and which does not cause debilitating side effects. In particular, it would be desirable to provide such treatment which can be used simultaneously with hormone therapy, allowing hormone therapy at lower (safer) dose rate and lower (safer) total doses, while providing effective results.